This invention relates generally to portable handrails which are mounted on the edges of a roof to protect workers thereon. More particularly, the present invention relates generally to portable handrail systems which are supported in place by a cantilever-type counterweight system.
Portable handrail or guard rail systems have long been employed to protect workers on roofs or elevated structures. Conventional portable handrail systems are modular systems which are assembled on a given job site in accordance with the specific work constraints. Commonly such systems employ a base which supports an upright post. These post assemblies are spaced along the edge of the roof. Rails connect between the upright posts to form the handrail system. Counterbalance assemblies extended from some of the bases. A number of such assemblies employ a bent cantilever arm which extends inwardly from the roof edge. A heavy weight is positioned to overlay an end portion of the cantilever arm. The weight conventionally takes the form of a concrete block or a similar mass with a handle to facilitate transporting the weight.
One conventional portable guard rail system marketed to the construction industry employs a multiplicity of bases. Each base has two vertical sockets for receiving the lower end of an inverted U-shaped modular rail unit. The bases have a generally square shape with a closed end recessed receptacle at each vertex. Each receptacle is dimensioned to receive the ends of a toeboard. Pins are employed to secure the guard rail units and toeboards to the bases.
In order to protect construction personnel on high rise construction projects, a number of regulatory provisions now require temporary protective railing structures. For example, floor openings, open sided floors, platforms and runways above a pre-established elevation may require guarding by a railing and a toeboard. Conventionally, the railing structure requires a top rail positioned approximately 42 inches from the upper surface of the floor or platform, an intermediate rail positioned between the top rail and the floor and a toeboard positioned along the bottom portion of the guard rail adjacent the floor. Because the guard rail systems are necessarily temporary and require assembly and disassembly, a key design feature is to provide a guard rail system which implements the required structural integrity, while also allowing for relatively easy disassembly and assembly on the job site. In addition, the geometry of the platform or area to be guarded may vary dramatically from construction site to construction site. Various fixed structures may also impact on the configuration of a specific guard rail system. For roof applications, one or more sides of the roof may have a parapet which also requires a guard rail.